Edward Kim is the CEO of SimpleReach, a provider of industry content performance measurement and distribution.

There are few people in our industry who are happy about the continued pervasiveness of click-through rates as the metric of a digital campaign’s success. And yet, no one can escape it. That is the power and lasting influence of industry standards, especially ones that are tied to a multibillion dollar economy.

As native advertising matures, industry standards are being created that, once settled, will again be virtually immovable. Let’s avoid making the same mistakes that got us here in the first place. Let’s avoid letting “engaged time” become the new metric of choice.

What exactly is wrong with CTR? If it were a robust, accurate measure of marketing success, there would be no issue. The problem stems from the fact that a single metric is necessarily limiting: One metric can never fully encompass the vast diversity of a marketer’s goals.

CTR made a lot more sense 20 years ago, when the industry’s measurement and attribution capabilities were less sophisticated, and there was relatively little available to measure. During that era, CTR served an important purpose as a proxy. If you couldn’t measure how your campaign drove consumers down a funnel or helped increase brand affinity, you could use CTR as a directional success metric.

Another challenge with rallying around a single metric is that once the industry chooses that metric, some will start “gaming” it. Once video marketers placed a higher premium on completed views, we saw the rise of gated content, views for in-game benefits and even views for free Wi-Fi, essentially incentivizing users to finish watching ads. Show me a metric, and I’ll show you someone gaming it.

I was on a panel where the moderator asked, “What is the single most important metric for native advertising success?” It’s a very tempting question to ask, and different voices are offering their answers. But by assuming there is a single success metric, we will find ourselves in exactly the same place we are in with CTR. Still, there are voices now pushing for “engaged time” to become the new defining metric for content marketing.

Let’s briefly consider the implications for marketers should this prevail.

The content that correlates with success isn’t always the most deeply read. If a marketer’s goal is to drive social sharing, for example, optimizing for time spent likely wouldn’t achieve the desired result. This is because, as the voices pushing for time-based metrics have acknowledged, engaged time doesn’t map closely to sharing. If an e-commerce brand is using content to drive sales or subscription sign-ups, then neither time nor sharing should be the key metric. Instead, the brand should focus on the only metric that really matters: conversions. Optimizing all campaigns for engaged time would severely limit the effectiveness of many.

One thing to understand about championing engaged time as the definitive metric of success is that it comes from the perspective of media companies. Engaged time is an important metric in assessing the health of a publisher’s audience, product and business. But as brands become publishers themselves, they need to remember that their business objectives are different, so their measure of success should differ as well.

Rather than relying on a single metric, I propose an alternative: Tell me your marketing goals, and I’ll tell you which metrics to focus on. Whether your goal is brand lift, conversation, engagement, sign-ups or purchases, we now have the data and tools needed to optimize each campaign for the specific metrics that matter most. Use them.